We are continuing our investigation of the mechanism and significance of the negative inotropic effects of inhalation anesthetics. In the coming year we plan to measure function and substrate extraction in unanesthetized, chronically instrumented dogs and then under various anesthetic doses. In addition we plan to study the same variable in patients at a chest surgery hospital in the Netherlands. At the same institution, we will measure the effect of anesthetics on ATP and phosphocreatine contents of pig hearts. These latter two studies should advance our understanding of the mechanism of the cardiac depressant effect of anesthetics and of the clinical significance of that mechanism.